Grahl Duo-Back® is equipped with a unique dual backrest, with the two elements moving independently of each other. Height adjustable, the backrests on the Grahl Duo-Back correctly support the back of any user. The space between the duo back pads allows the spine to move freely. Instead of putting pressure on the spine, support is evenly distributed throughout the back muscles. The duoback backrests are pivotally mounted enabling them to move in all three axes – forwards and backwards, up and down and left to right. The type 11 and 12 is the most popular range, with a synchronous movement mechanism, whilst the Ergonom 67 range has the option of a split seat mechanism. SPS has a multi-lock tilting action with weight tension control and a seat angle adjustment of +5 to -14º, and is for many the most comfortable model.